First, thank you very much for your amazing Snesgt emulator !
A few things :

- Could you add more window sizes ? 2x is too small to me, while x3 is a bit big. Things like 2.5 etc would be nice imho.

- Could you consider supporting mame rgb masks system ? These are simple png displayed over the image, and it gives great results while using no cpu at all. It's called "mame overlay effects".

- Could we have more configurable scanlines ? Actually, with the right settings, bilinear + scanlines can look great. Nestopia, using 30% scanlines + interpolation, looks much smoother than snesgt.
(i guess the % thing is for scanlines brightness...)